Pollen drying and storage for hybrid seed production of cucumber (Cucumis sativus L.)

Abstract

One of the major problems in hybrid seed production of cucumbers is the low pollen production and low pollen viability. This research was mainly dealt with pollen handling in order to maintain its viability during storage, which was carried out in three steps. Male parental of 'KE014' was planted at Production Farm of East West Seed Indonesia Ltd. in Jember, East Java, Indonesia during March to September 2012. In a first step, male flowers were harvested and pollen was extracted and dried for 24 h during which the water content and pollen viability was monitored. In a second step the dried pollen was stored in an ultra-freezer (-79±2°C) for 56 days and its viability was also monitored every 7 days. The third step was the pollination of a female parental stock to produce hybrid seed. The experiments were arranged in three replications with completely randomized design. Results showed that pollen water content decreased significantly during the first 8 h of drying from 12.05 to 6.71% while the pollen viability increased from 10.16 to 25.60%. Prolonged pollen drying time up to 24 h did not substantially reduce the water content. Pollen dried for 8 h was able to maintain its viability during 56 days of storage in ultra-freezer (-79±2°C) better than those undried or dried longer. The fruit set and seed set got from pollination with undried and stored pollen (11.0 and 23.0%, respectively) was lower than fruit set and seed set got with dried and stored pollen (ranged 46.5-58.9 and 52.0-67.8%, respectively). Using stored pollen (undried or dried) for pollination in hybrid seed production yielded in lower number of filled seed per fruit than using fresh pollen. Hybrid seed germination got from pollination with dried and stored pollen was slightly higher (98.36-99.63%) than those got from undried and stored pollen (95.58%), nevertheless all of them were high quality seeds. Thus, using the stored pollen for pollination in cucumber hybrid seed production would reduce seed yield but not seed quality.